Diagnosis and Management of Paget's Disease of Bone in Adults: A Clinical Guideline

From bimodal to unimodal: The transformed incidence of osteosarcoma in the United States

Background

Osteosarcoma is the most common primary bone malignancy. It has classically been described as having a bimodal incidence by age. We sought to identify whether the bimodal incidence distribution still exists for osteosarcoma using the SEER and NIS databases.

Methods

Incidence rates of primary osteosarcoma between 2000-2021 were analyzed by age at diagnosis, year of occurrence, sex, and tumor site from the SEER Research Data, 17 Registries, Nov 2023 Sub (2000-2021). The incidence of cases in 35-64 year-olds and 65 and above was compared statistically to determine if there is an increased incidence in the later ages. Incidence of tumors of the long bones of the lower limbs from the NIS discharge database 2012-2019 was also analyzed for comparison.

Results

Overall, 5,129 cases of osteosarcoma were reported in the SEER database. Across the 22 calendar year span, a consistent first peak appeared in the second decade of life. There was no consistent second peak in the 35+ age group. There were 86,100 discharges with long bone tumors analyzed in the NIS data which exhibited nearly identical patterns.

Conclusions

Our analysis shows that the incidence of osteosarcoma is no longer bimodally distributed but rather unimodally distributed.

Surgical decompression in spinal Paget's disease: illustrative case

BACKGROUND

Paget's disease of bone (PDB) is a common bone metabolic pathology in older adults, characterized by mixed osteolytic, osteoblastic, and quiescent periods. Surgical guidelines for PDB involving the spine are not well-defined and are reserved for cases refractory to medical treatments, typically bisphosphonates like zoledronic acid. This case study describes a 52-year-old male with PDB who presented with rapidly progressing myelopathy symptoms refractory to standard medical treatment, warranting surgical decompression.

OBSERVATIONS

Surgical decompression and fusion, involving laminectomy with partial facetectomies, placement of pedicle screw instrumentation, and posterolateral arthrodesis spanning beyond the pathological segment, was performed. Follow-up visits indicated progressive improvement in symptoms and mobility, and imaging showed stable postsurgical changes with increased sclerosis in the affected vertebrae on a 2-year postsurgical course.

LESSONS

This case underscores that PDB of the spine can transition from asymptomatic to significant impairment and demonstrates that surgical intervention can provide effective symptomatic relief in myelopathy secondary to PDB. The case contributes to the growing evidence of the effectiveness of surgical decompression in PDB involving the spine. https://thejns.org/doi/10.3171/CASE24203.

Paget disease of bone in a southeastern Veteran population

BACKGROUND

Paget disease of bone (PDB) is a disorder of accelerated bone remodeling resulting in bone overgrowth and impaired integrity that traditionally is described to be more frequent in individuals of European descent. Based on clinical observation, we hypothesized that among the US Southeastern Veteran population, the disease is more common among African American patients.

MATERIALS AND METHODS

We conducted a cross-sectional study using the Veterans Affairs' Clinical Data Warehouse (CDW) and review of electronic medical records (EMR). Using the CDW, we identified patients from the Birmingham VA Medical Center (BVAMC) with an International Classification of Diseases code for PDB between January 2000 and December 2020. We extracted their self-reported race from the CDW and determined the proportion of African American patients, which we compared to the proportion of White patients. As a secondary goal, we extracted relevant clinical characteristics from the EMR. The statistical analysis was done using Stata/SE 14.2 for Mac.

RESULTS

We identified 285 individuals from the BVAMC with PDB between January 2000 and December 2020. The proportion of African American patients was significantly higher than White patients (0.51 vs. 0.4, p = 0.0036). African American patients presented at a younger age than their peers (mean[standard deviation] age at diagnosis: 64.6[11.6] vs. 70.1[10.7] years, p = 0.0009) but did not have higher alkaline phosphatase levels, higher proportion of polyostotic disease, or of symptoms and complications.

CONCLUSIONS

In the BVAMC population, PDB is more common among African American patients than White patients. Our findings and other publications hint at the existence of a cluster of PDB among the African American population in the US Southeast.

Diagnosis and treatment of Paget's disease of bone: position paper from the Italian Society of Osteoporosis, Mineral Metabolism and Skeletal Diseases (SIOMMMS)

INTRODUCTION

Paget's disease of bone is a focal skeletal disorder causing bone deformities and impairing bone quality. Despite the prevalence of asymptomatic cases is increasing, the progression of the disease can lead to invalidating complications that compromise the quality of life. Doubts on clinical and therapeutic management aspects exist, although beneficial effects of antiresorptive drugs, particularly bisphosphonates are known. However, limited information is available from randomized controlled trials on the prevention of disease complications so that somewhat contrasting positions about treatment indications between expert panels from the main scientific societies of metabolic bone diseases exist. This task force, composed by expert representatives appointed by the Italian Society of Osteoporosis, Mineral Metabolism and Skeletal Diseases and members of the Italian Association of Paget's disease of bone, felt the necessity for more specific and up to date indications for an early diagnosis and clinical management.

METHODS

Through selected key questions, we propose evidence-based recommendations for the diagnosis and treatment of the disease. In the lack of good evidence to support clear recommendations, available information from the literature together with expert opinion of the panel was used to provide suggestions for the clinical practice.

RESULTS AND CONCLUSION

Description of the evidence quality and support of the strength of the statements was provided on each of the selected key questions. The diagnosis of PDB should be mainly based on symptoms and the typical biochemical and radiological features. While treatment is mandatory to all the symptomatic cases at diagnosis, less evidence is available on treatment indications in asymptomatic as well as in previously treated patients in the presence of biochemical recurrence. However, given the safety and long-term efficacy of potent intravenous bisphosphonates such as zoledronate, a suggestion to treat most if not all cases at the time of diagnosis was released.

Canadian Association of Radiologists Musculoskeletal System Diagnostic Imaging Referral Guideline

The Canadian Association of Radiologists (CAR) Musculoskeletal System Expert Panel consists of musculoskeletal radiologists, a family physician, a sports and exercise medicine physician, emergency medicine physicians, a patient advisor, and an epidemiologist/guideline methodologist. After developing a list of 25 musculoskeletal clinical/diagnostic scenarios, a systematic rapid scoping review was undertaken to identify systematically produced referral guidelines that provide recommendations for 1 or more of these clinical/diagnostic scenarios. Recommendations from 41 guidelines (50 publications) and contextualization criteria in the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) for guidelines framework were used to develop 124 recommendation statements across the 25 scenarios related to the evaluation of the musculoskeletal system. This guideline presents the methods of development and the recommendations for imaging in the context of musculoskeletal pain, infection, tumors, arthropathies, metabolic bone disease, stress injuries, orthopedic hardware, avascular necrosis/bone infarction, and complex regional pain syndrome.

Paget Disease of Bone Harboring Bone Metastatic Neuroendocrine Cancer: A Case Report

In this case report, we describe an uncommon case of neuroendocrine cancer of unknown origin began with cauda equina syndrome in a patient affected by Paget disease of bone (PDB). A 76-year-old man with diagnosis of PDB, without history of pain or bone deformity, developed sudden severe low back pain. Bone alkaline phosphatase was increased and MRI and whole-body scintigraphy confirmed the localization of the disease at the third vertebra of the lumbar spine. Treatment with Neridronic Acid was started, but after only 2 weeks of therapy anuria and bowel occlusion occurred together with lower limb weakness and walking impairment. Cauda equina syndrome consequent to spinal stenosis at the level of L2-L3 was diagnosed after admission to Emergency Department and the patient underwent neurosurgery for spinal medulla decompression. The histologic results showed a complete subversion of bone structure in neoplastic tissue, consistent with metastatic neuroendocrine carcinoma of unknown origin. In conclusion, low back pain in the elderly may require deep investigation to individuate rare diseases. In asymptomatic patients with apparently stable PDB, the sudden appearance of pain or neurologic symptoms may alert the clinician for the possibility of other superimposing diseases, like bone metastases.

Radiological impact of oral bisphosphonate use on polyostotic Paget's disease of bone over a 2 year period

Paget's disease of bone is a disorder of osteoclasts which hampers the physiological process of bone remodeling. It is the most common metabolic orthopedic disease in the Caucasian populace; we report the diagnosis of Paget's disease of bone in a South-Asian male in his early 50s with a history of gastrointestinal symptoms, weight loss and back pain. An alkaline phosphatase level of 1104 IU/L was noted. A 3-phase bone scan showed noncontiguous heterogenous nuclear uptake. After exhaustive evaluation, the patient was diagnosed with Paget's disease of bone. Despite the disease activity being mitigated by alendronate and monitored by ALP levels within normal range per protocol, the patient had compression fractures of the vertebrae requiring early reinitiation of oral bisphosphonates. This raised doubts about the efficacy of metabolic marker-based management in Paget's disease of bone.

Long-term effectiveness of zoledronic acid in patients with Paget's disease of bone - a retrospective cohort study

PURPOSE

The aims of the current study were to describe clinical and biochemical features of patients with Paget disease of bone (PDB) followed at our medical center, and to examine the long-term effectiveness of zoledronate.

METHODS

Retrospective cohort study included consecutive patients≥18 years with a diagnosis of PDB, followed in the Rabin Medical Center (RMC) Institute of Endocrinology from 1973 to 2023. The cohort comprised two groups: patients treated/not treated with zoledronic acid (ZOL/NZOL). The primary outcome was the percentage of patients who achieved a biochemical therapeutic response.

RESULTS

Overall, 101 patients with PDB were included, 68 in the ZOL group and 33 in the NZOL group. The mean age was 65.2 ± 10.0 years, and 47% were female. Notably, 77% exhibited monostotic involvement, and only 3% had experienced fractures attributed to PDB. Mean ALP level at diagnosis was 160 ± 70.6 U/L. The median follow-up duration was 17 years since PDB diagnosis, comparable between the groups. Primary outcome was more prevalent in the ZOL compared to the NZOL group [42 patients (88%) VS 11 patients (52%) respectively, P = 0.004]. At the end of follow-up, mean ALP levels in the NZOL group were significantly higher than the levels in the ZOL group irrespective of the number of infusions received.

CONCLUSION

The majority of patients with PDB experience a mild disease course, marked by monostotic involvement and a low prevalence of fractures. Zoledronic acid effectively manages PDB, providing sustained biochemical response. The necessity for multiple zoledronic acid injections remains questionable, often implemented due to osteoporosis.

Bone scan findings of Paget's disease of bone in patients with VCP Multisystem Proteinopathy 1

Multisystem Proteinopathy 1 (MSP1) disease is a rare genetic disorder caused by mutations in the Valosin-Containing Protein (VCP) gene with clinical features of inclusion body myopathy (IBM), frontotemporal dementia (FTD), and Paget's disease of bone (PDB). We performed bone scan imaging in twelve patients (6 females, 6 males) with confirmed VCP gene mutation six (50%) of which has myopathy alone, four (33%) with both PDB and myopathy, and two (15%) were presymptomatic carriers. We aim to characterize the PDB in diagnosed individuals, and potentially identify PDB in the myopathy and presymptomatic groups. Interestingly, two patients with previously undiagnosed PDB had positive diagnostic findings on the bone scan and subsequent radiograph imaging. Among the individuals with PDB, increased radiotracer uptake of the affected bones were of typical distribution as seen in conventional PDB and those reported in other MSP1 cohorts which are the thoracic spine and ribs (75%), pelvis (75%), shoulder (75%) and calvarium (15%). Overall, we show that technetium-99m bone scans done at regular intervals are a sensitive screening tool in patients with MSP1 associated VCP variants at risk for PDB. However, diagnostic confirmation should be coupled with clinical history, biochemical analysis, and skeletal radiographs to facilitate early treatment and prevention complications, acknowledging its limited specificity.

The Use of Bone-Turnover Markers in Asia-Pacific Populations

Bone-turnover marker (BTM) measurements in the blood or urine reflect the bone-remodeling rate and may be useful for studying and clinically managing metabolic bone diseases. Substantial evidence supporting the diagnostic use of BTMs has accumulated in recent years, together with the publication of several guidelines. Most clinical trials and observational and reference-interval studies have been performed in the Northern Hemisphere and have mainly involved Caucasian populations. This review focuses on the available data for populations from the Asia-Pacific region and offers guidance for using BTMs as diagnostic biomarkers in these populations. The procollagen I N-terminal propeptide and β-isomerized C-terminal telopeptide of type-I collagen (measured in plasma) are reference BTMs used for investigating osteoporosis in clinical settings. Premenopausal reference intervals (established for use with Asia-Pacific populations) and reference change values and treatment targets (used to monitor osteoporosis treatment) help guide the management of osteoporosis. Measuring BTMs that are not affected by renal failure, such as the bone-specific isoenzyme alkaline phosphatase and tartrate-resistant acid phosphatase 5b, may be advantageous for patients with advanced chronic kidney disease. Further studies of the use of BTMs in individuals with metabolic bone disease, coupled with the harmonization of commercial assays to provide equivalent results, will further enhance their clinical applications.

Safety and effectiveness of risedronate in Paget's disease of bone: postmarketing surveillance study in Japan

INTRODUCTION

We conducted an all-case postmarketing surveillance study between 2008 and 2017 to evaluate the safety and effectiveness of risedronate for Paget's disease of bone (PDB) in Japan.

MATERIAL AND METHODS

This study registered all patients who received once-daily risedronate 17.5 mg for the treatment of PDB and collected data over a 48-week follow-up period per treatment cycle for each patient.

RESULTS

The safety analysis set included 184 patients (mean age, 63.7 years), 81 (44.0%) of whom previously received a bisphosphonate. Of them, 41 (22.3%) experienced 72 adverse drug reactions (ADRs), and 8 (4.3%) experienced 14 serious ADRs. Common ADRs included gastrointestinal disorders (20 patients, 10.9%) and hypocalcemia (6 patients, 3.3%). The effectiveness analysis set included 182 patients, 124 of whom completed only one treatment cycle and 58 of whom completed multiple treatment cycles. The proportions of patients who normalized serum alkaline phosphatase (ALP) concentration were 71.1% (113/159 patients) and 67.3% (33/49 patients) for the first and second treatment cycles, respectively. The relapse rate according to ALP levels after the end of treatment for the first cycle was 5.0% (95% confidence interval [CI] = 2.1-11.5) at 24 weeks and 12.9% (95% CI = 7.5-21.7) at 40 weeks. Regarding pain relief, the achievement rates were 70.0% (49/70 patients) and 30.8% (4/13 patients) for the first and second treatment cycles, respectively.

CONCLUSION

To conclude, risedronate 17.5 mg/day is safe and effective for treating patients with PDB in daily practice.

The Role of Genetic Analysis in Demystifying the Diagnosis in a Middle-Aged Male Presenting With Proximal Muscle Weakness and Sclerotic-Lytic Skeletal Lesions

Paget's disease of bone (PDB) usually presents with bone pain and deformities. Herein, we describe a case of PDB who presented with gradually progressive quadriparesis. A man in his forties presented with gradually progressive proximal muscle weakness involving all four limbs. The patient had an elevated serum alkaline phosphatase level and osteosclerosis at various skeletal sites in a radiological skeletal survey. 18F-fluorodeoxyglucose (FDG) PET-CT showed FDG-avid sclerotic-lytic lesions at multiple skeletal sites. Histopathology evaluation of bone and muscle biopsy specimens revealed PDB and inclusion body myopathy (IBM) with neurogenic atrophy, respectively. A diagnosis of IBM associated with PDB without frontotemporal dementia (IBMPFD) was suspected and confirmed by exome sequencing, which revealed a heterozygous mutation in the VCP gene. The bone disease responded to zoledronate administration. A high index of suspicion for IBMPFD should be kept in mind in any patient with PDB presenting with proximal muscle weakness.

Paget's Disease of Bone: A Rare Incidence in Early Adult Life in Pakistan, Southeast Asia

Paget's disease of bone (PDB) is a focal disorder of skeletal remodeling leading to alteration of bony structures and properties, uncommonly reported in people under the age of 40 years, particularly in the Southeast Asia region. In the literature, PDB has been well reported in regions of Europe, in contrast to Asia where there has been limited records of prevalence of PDM especially in the younger age population. Here, we report a 21-year-old male patient presenting with an advanced disease with complaints of auditory impairment, bone pain, and neurological signs due to compression of the interverbal disc developed progressively over two months, having an elevated serum alkaline phosphatase level of 601 IU/L. The patient was administered zoledronic acid that brought significant improvement in his health. We aim to signify the advanced presentation of PDB in our region to create awareness about the condition among physicians and aid in the prompt diagnosis and prevention of the most dreaded complications of the disease, such as osteosarcoma, secondary osteoarthritis, and fractures.

Paget's disease of bone in the patient presented with a bowed leg

Key Clinical Message

In dealing with bowed limbs along with increased alkaline phosphatase (ALP), even if the typical changes to the face are not very noticeable at first glance, Paget's disease of the bone (PDB) should be suspected, and the necessary investigations should be carried out to confirm the diagnosis.

Abstract

Paget's disease of the bone (PDB) is the second most prevalent metabolic bone disorder worldwide with disorganized bone remodeling. Here, a patient is presented with pain and bending of the right leg, whose skull and forehead changes are not noticeable at first glance, but with clinical suspicion and additional diagnostic evaluations, PDB diagnosis is confirmed for the patient.

A Narrative Review of Osteonecrosis of the Jaw: What a Clinician Should Know

Medication-related osteonecrosis of the jaw (MRONJ) is an uncommon complication of antiresorptive therapy (ART) in patients receiving higher and more frequent doses of osteoclast inhibitors. The jaws are the most common site, as they have high bone turnover. The oral structures are exposed to various types of stresses, like mastication and dental diseases, which lead to microtrauma and increased bone remodeling. The hallmark feature of MRONJ is the area of exposed, necrotic, nonhealing, asymptomatic bone for more than eight weeks. Objective signs are pain in the jaw and oral cavity, loose teeth, gingival swelling, ulceration, soft tissue infection, and paresthesia in the trigeminal nerve branches' territory. Clinically, the MRONJ has been defined in four stages, from stage 0 to stage 3. Close coordination between the dentist and oncologist is critical for optimal treatment. Conservative management should be preferred over surgical management. There is significant underreporting and misdiagnosis of MRONJ cases in regular clinical practice. There needs to be more awareness among treating physicians about this sporadic complication of bisphosphonate therapy. This narrative review has given a detailed insight into the subject, starting with etiology, pathogenesis, incidence, clinical presentation, workup, staging, and various management strategies. The review article focuses mainly on practical aspects of MRONJ, which every clinician dealing with the disease must know. With a better awareness of this potential complication, healthcare practitioners dealing with at-risk patients can better diagnose, prevent, address, and provide necessary care.

Prevalence and incidence of Paget's disease of bone: Temporal trend over 20 years in the province of Quebec, Canada

BACKGROUND

Paget's disease of bone (PDB) is a focal bone disorder characterized by an increased bone remodeling and an anarchic bone structure. A decline of prevalence and incidence of PDB has been observed in some countries. No epidemiological data are available on PDB in Canada.

AIMS

We aimed at examining the evolution of the prevalence and incidence of PDB in Quebec (Canada) by analyzing health administrative databases.

METHODS

PDB case definition relied on one or more hospitalizations, or one or more physician-billing claims with a diagnosis code of PDB. To identify incident cases, a 'run-in' period of four years (1996-1999) was used to exclude prevalent cases. For each fiscal year from 2000 to 2001 to 2019-2020 (population size 2,914,480), crude age and sex-specific prevalence and incidence rates of PDB among individuals aged ≥55 years were determined, and sex-specific rates were also standardized to the 2011 age structure of the Quebec population. Generalized linear regressions were used to test for linear changes in standardized prevalence and incidence rates.

RESULTS

Over the study period, standardized prevalence of PDB has remained stable in Quebec, from 0.44 % in 2000/2001 to 0.43 % in 2019/2020 (mean change -0.002, p-value = 0.0935). For the 2019-2020 fiscal year, 13,165 men and women had been diagnosed with PDB and prevalence of PDB increased with age. Standardized incidence of PDB has decreased over time from 0.77/1000 in 2000/2001 to 0.28/1000 in 2019-2020 (mean change -0.228/year, p-value<0.0001), the incidence decreasing from 0.82/1000 to 0.37/1000 in men and from 0.76/1000 to 0.22/1000 in women, respectively. This decrease was observed in all age categories.

CONCLUSION

With the exception of a slight increase in PDB prevalence up to 0.55 % in years 2005 to 2007, the prevalence of PDB has remained stable in Quebec over the past 20 years, 13,160 men and women being currently diagnosed with PDB. The incidence has decreased over time. Our results support the epidemiological changes of PDB reported in other countries.

Bisphosphonates and osteonecrosis of the jaws: Clinical and forensic aspects

OBJECTIVE

This manuscript aims to provide a comprehensive review of the current knowledge in the pathophysiology, diagnosis, prevention, and other relevant clinical and forensic aspects of a potentially severe complication known as medication-related osteonecrosis of the jaw (MRONJ) while synthesizing state-of-the-art information on bisphosphonates and introducing a possible differential diagnosis.

DESIGN

An extensive search was conducted in PubMed (U.S. National Library of Medicine) without a time or language constraint, focusing on the epidemiology, pathophysiology, risk factors, site specificity, signs and symptoms, differential diagnosis, prevention, and forensic aspects of MRONJ. All types of original articles, reviews, case reports, short communications, opinion articles, guidelines, and letters to editors were considered to produce a complete review on this subject.

RESULTS

MRONJ prevention relies on a multidisciplinary approach and is critical since truly effective treatments are lacking. This therapeutic challenge is partly due to uncertainty regarding this condition's pathophysiology. Differential diagnosis of osteonecrosis of the jaws associated with krokodil abuse, one of the most dangerous and homemade psychoactive illicit substances, should be considered.

CONCLUSIONS

Further research into the etiology and site specificity of MRONJ is encouraged, aiming to develop novel treatment prospects. Indeed, comprehending this would allow for increased efficacy and therapeutic options while emphasizing the importance of prevention. In addition, we advocate for greater consensus among the various societies regarding MRONJ's treatment and management.

Osteolytic Bone Loss and Skeletal Deformities in a Mouse Model for Early-Onset Paget's Disease of Bone with PFN1 Mutation Are Treatable by Alendronate

A novel osteolytic disorder due to PFN1 mutation was discovered recently as early-onset Paget's disease of bone (PDB). Bone loss and pain in adult PDB patients have been treated using bisphosphonates. However, therapeutic strategies for this specific disorder have not been established. Here, we evaluated the efficiency of alendronate (ALN) on a mutant mouse line, recapitulating this disorder. Five-week-old conditional osteoclast-specific Pfn1-deficient mice (Pfn1-cKOOCL) and control littermates (33 females and 22 males) were injected with ALN (0.1 mg/kg) or vehicle twice weekly until 8 weeks of age. After euthanizing, bone histomorphometric parameters and skeletal deformities were analyzed using 3D μCT images and histological sections. Three weeks of ALN administration significantly improved bone mass at the distal femur, L3 vertebra, and nose in Pfn1-cKOOCL mice. Histologically increased osteoclasts with expanded distribution in the distal femur were normalized in these mice. Geometric bone shape analysis revealed a partial recovery from the distal femur deformity. A therapeutic dose of ALN from 5 to 8 weeks of age significantly improved systemic bone loss in Pfn1-cKOOCL mice and femoral bone deformity. Our study suggests that preventive treatment of bony deformity in early-onset PDB is feasible.

Total Knee Arthroplasty in Paget's Disease using 3D-Printed Patient-Specific Femoral Jig - A Case Report

Introduction

Patients with Paget's disease develop abnormal bony anatomy which can result in significantly altered lower limb alignment predisposing them to early secondary osteoarthritis. Due to the severe extra-articular deformity, total knee arthroplasty (TKA) in these patients is challenging. Conventional knee arthroplasty using intramedullary guides is not an option and can lead to erroneous limb alignment postoperatively. Patient-specific instrumentation (PSI) is a simple solution in such complex primary knee arthroplasty.

Case Report

A 70-year-old male patient presented with a severe left femur deformity and left knee pain. He was diagnosed to have monostotic Paget's disease of the left femur with tricompartmental osteoarthritis of the left knee. After reduction in pathological bone turnover, the patient was planned for a total knee replacement. As a standard intramedullary femoral jig was not applicable due to the femoral deformity, a computed topography-based 3D-printed patient-specific instrument was used. This custom jig was used to define and perform the distal femur cut at 90 degrees to the mechanical axis of the femur in the coronal and sagittal plane. Postoperatively, the patient did well and achieved good function and pain relief.

Conclusion

The use of a 3D-printed PSI for complex primary knee arthroplasty is an excellent option with no additional operative time than a conventional knee arthroplasty. Although a robotic or computer-navigated TKA would be an excellent option in this case, we restored the limb alignment using a cost-effective patient-specific femoral jig. This could be a viable option in centers without navigation or robotic arthroplasty.

PAGET'S DISEASE OF THE BONE FOUND INCIDENTALLY ON F-18 FDG PET/CT: CLINICAL SIGNIFICANCE AND DIFFERENTIAL DIAGNOSTIC CRITERIA

Background

Paget Disease (PD) is usually asymptomatic and discovered incidentally, it is known that it is exhibited low to high grade increased F-18 FDG uptake.

Aim

In this study, we investigated the distinguishability of FDG PET/CT in incidental PD cases from other bone diseases and at different stages of the disease.

Patients and Methods

In this cross-sectional, descriptive study, "Paget" identification associated with PET/CT reports was found in 69 of 18,119 studies (~3.8%). Of the 45 patients (33 males and 12 females) eligible for inclusion in the study, 35.6% had monostotic and 64.4% had polyostotic disease (p>0.5). There was no statistically significant difference in biochemical parameters between groups.

Results

According to the radiological appearance of the patients, 36 were in the mixed stage and 9 were in the blastic stage. Only the difference in ALP and creatinine values between the groups was statistically significant. SUVmax, SUVmean and HU values were found to be statistically significantly higher in pagetoid bones compared to control bone lesions. For SUVmax for PD bone lesion we found the 2.55 cutoff point with a sensitivity of 91% and a specificity of 84%.

Conclusion

The specific radiological appearance of bone lesions and the evaluation of metabolic activity compared to normal bone seem to help differentiate PD from other lesions. Prospective studies are needed in the differentiation of FDG's disease stage and treatment response evaluation. The ability to differentiate between benign and malignant FDG avid bone lesions in oncological patients' enables appropriate patient management, including avoiding unnecessary additional invasive procedures such as bone biopsy.

Imaging of Skull Base Tumors

The skull base provides a platform for supporting the brain while serving as a conduit for major neurovascular structures. In addition to malignant lesions originating in the skull base, there are many benign entities and developmental variants that may simulate disease. Therefore, a basic understanding of the relevant embryology is essential. Lesions centered in the skull base can extend to the adjacent intracranial and extracranial compartments; conversely, the skull base can be secondarily involved by primary extracranial and intracranial disease. CT and MRI are the mainstay imaging methods and are complementary in the evaluation of skull base lesions. Advances in cross-sectional imaging have been crucial in the management of patients with skull base pathology, as this represents a complex anatomical area that is hidden from direct clinical exam. Furthermore, the clinician must rely on imaging studies for therapy planning and to monitor treatment response. It is crucial to have a thorough understanding of skull base anatomy and its various pathologies, as well as to recognize the appearance of treatment-related changes. In this review, we aim to describe skull base tumors and tumor-like lesions in an anatomical compartmental approach and present imaging methods that aid in diagnosis, management, and follow-up.

Decline in clinical severity of Paget's disease of bone: Comparison between a contemporary cohort and a historical cohort

BACKGROUND

European and Australian studies have reported a decrease in the prevalence, incidence and clinical severity of Paget's disease of bone (PDB). There are no studies on the current clinical characteristics of PDB in Quebec, Canada.

AIMS

The purpose of this study was to describe the characteristics of unrelated patients with PDB diagnosed after the year 2000 in our region and to compare them to a historical cohort diagnosed before 2000.

METHODS

In this retrospective descriptive cohort study, socio-demographic data and clinical characteristics for the contemporary cohort were collected from electronic medical records of patients with PDB followed at our university hospital. For the historical cohort, the same data were collected from the research files of PDB participants in our research program. Inclusion criteria were: age > 18 years, having PDB diagnosed by a rheumatologist, and being followed in our hospital. Exclusion criteria were: having a relative with PDB participating in this study. Variables were reported as mean, standard deviation, frequency and percentage. Chi-square tests were used to compare categorical variables. Continuous values were compared with Wilcoxon-Mann-Whitney tests. Unadjusted p-values and adjusted p-values with the Bonferroni correction method were calculated. A p-value <0.05 was considered statistically significant.

RESULTS

Among the 195 patients with PDB in the contemporary cohort, 53.3 % were men, 60.5 % had monostotic involvement, 14.2 % were symptomatic at diagnosis. In comparison to the historical cohort of 173 patients, patients in the contemporary cohort were older at diagnosis (68.7  10.7 vs. 58.5  10.1; p < 0.0001) and had less family history of PDB (13.8 % vs. 33.6 %; p = 0.0024). They also had lower total alkaline phosphatase levels at diagnosis (118.0 (85.0-184.0)) vs. 184.0 (115.0-312.0)); p = 0.0006), a lower pagetic bone number (1.0 (1.0-3.0) vs. 2.0 (1.0-5.0); p < 0.0001), lower pagetic bone fractures (6.7 % vs. 36.7 %; p = 0.0078) and lower bone deformities (13.0 % vs. 54.0 %; p < 0.0001). There was no significant difference for pagetic bone pain (52.0 % vs. 52.6 %; p = 1.0000), percentage of patients who had orthopedic surgery related to PDB complications (8.8 % vs. 28.6 %; p = 1.0000), secondary osteoarthritis (43.0 % vs. 51.6 %; p = 1.0000), and hearing impairment (51.9 % vs. 61.1 %; p = 0.1000).

CONCLUSION

The contemporary cohort is characterized by an older age at diagnosis, a majority of monostotic disease and fewer complications of PDB. This decline in clinical severity of PDB in Quebec is consistent with studies reported in other countries.

Paget's disease: a review of the epidemiology, etiology, genetics, and treatment

Paget's disease of bone (PDB) is the second most prevalent metabolic bone disorder worldwide, with a prevalence rate of 1.5%-8.3%. It is characterized by localized areas of accelerated, disorganized, and excessive bone production and turnover. Typically, PDB develops in the later stages of life, particularly in the late 50s, and affects men more frequently than women. PDB is a complex disease influenced by both genetic and environmental factors. PDB has a complex genetic basis involving multiple genes, with SQSTM1 being the gene most frequently associated with its development. Mutations affecting the UBA domain of SQSTM1 have been detected in both familial and sporadic PDB cases, and these mutations are often associated with severe clinical expression. Germline mutations in other genes such as TNFRSF11A, ZNF687 and PFN1, have also been associated with the development of the disease. Genetic association studies have also uncovered several PDB predisposing risk genes contributing to the disease pathology and severity. Epigenetic modifications of genes involved in bone remodelling and regulation, including RANKL, OPG, HDAC2, DNMT1, and SQSTM1, have been implicated in the development and progression of Paget's disease of bone, providing insight into the molecular basis of the disease and potential targets for therapeutic intervention. Although PDB has a tendency to cluster within families, the variable severity of the disease across family members, coupled with decreasing incidence rates, indicates that environmental factors may also play a role in the pathophysiology of PDB. The precise nature of these environmental triggers and how they interact with genetic determinants remain poorly understood. Fortunately, majority of PDB patients can achieve long-term remission with an intravenous infusion of aminobisphosphonates, such as zoledronic acid. In this review, we discuss aspects like clinical characteristics, genetic foundation, and latest updates in PDB research.

Drug treatment strategies for Paget's disease: relieving pain and preventing progression

INTRODUCTION

Paget's disease of bone (PDB) is a focal bone disorder caused by a marked dysregulation of osteoblasts and osteoclasts in basic multicellular units, leading to abnormal and disorganized deposition of collagen fibers (the so-called "woven bone"). Therefore, pagetic bones are increased in size, and at increased risk for bone pain, deformities, fractures, osteoarthritis, and, more rarely, neoplastic degeneration.

AREAS COVERED

In this review we revise the available information concerning the pharmacological treatment of PDB.

EXPERT OPINION

PDB progresses slowly within the affected skeletal sites and, if untreated, often leads to bone overgrowth, with bone pain, deformity and a likely increased risk of complications. Thus, the primary goal of treatment is the restoration of a normal bone turnover, in order to relieve bone pain or other symptoms and possibly prevent the complications. PDB long remained a poorly treatable disorder until the discovery of antiresorptive agents such as calcitonin first and bisphosphonates (BPs) later. With the recent development of potent intravenous BPs like zoledronate, allowing a better control of disease activity over the long term with a single infusion, has contributed to a marked improvement of the clinical management of this invalidating disorder.

Bone Turnover Markers: Basic Biology to Clinical Applications

Bone turnover markers (BTMs) are used widely, in both research and clinical practice. In the last 20 years, much experience has been gained in measurement and interpretation of these markers, which include commonly used bone formation markers bone alkaline phosphatase, osteocalcin, and procollagen I N-propeptide; and commonly used resorption markers serum C-telopeptides of type I collagen, urinary N-telopeptides of type I collagen and tartrate resistant acid phosphatase type 5b. BTMs are usually measured by enzyme-linked immunosorbent assay or automated immunoassay. Sources contributing to BTM variability include uncontrollable components (e.g., age, gender, ethnicity) and controllable components, particularly relating to collection conditions (e.g., fasting/feeding state, and timing relative to circadian rhythms, menstrual cycling, and exercise). Pregnancy, season, drugs, and recent fracture(s) can also affect BTMs. BTMs correlate with other methods of assessing bone turnover, such as bone biopsies and radiotracer kinetics; and can usefully contribute to diagnosis and management of several diseases such as osteoporosis, osteomalacia, Paget's disease, fibrous dysplasia, hypophosphatasia, primary hyperparathyroidism, and chronic kidney disease-mineral bone disorder.

Influence of type 2 diabetes microangiopathy on bone mineral density and bone metabolism: A meta-analysis

Background

Diabetic microangiopathy is a type of vascular dysfunction. The effect of type 2 diabetes microangiopathy (DMA) on bone mineral density (BMD) and bone metabolism is still unclear.

Objective

A meta-analysis was performed to investigate the effects of microangiopathy on BMD and bone metabolism in type 2 diabetic patients.

Methods

We searched the PubMed, Embase, Cochrane Library and CNKI databases to identify observational studies investigating the effects of type 2 diabetes microangiopathy on BMD or bone metabolism. The time limit for the literature retrieval was from the establishment of the database to September 25, 2021. The Newcastle–Ottawa scale (NOS) and the Agency for Healthcare Research and Quality (AHRQ) scale were used to evaluate the quality of the studies. RevMan 5.3 software was used for the data analysis. Stata 14.0 was used to quantitatively evaluate the publication bias of the outcome indicators.

Results

In total, 12 observational studies were included, including 7 cohort studies, 4 case–control studies and 1 cross-sectional study. In total, 2,500 patients with type 2 diabetes were included. Among them, 1,249 patients had microangiopathy (DMA group), and 1,251 patients did not have microangiopathy (control group). The results of the meta-analysis showed that the BMDs of the femoral neck (SMD = −1.34, 95% CI = −2.22 to −0.45, P = 0.003), lumbar spine (SMD = −0.69, 95% CI = −1.31 to −0.08, P = 0.03) and Ward's triangle (SMD = −2.84, 95% CI = −4.84 to −0.83, P = 0.006) in the DMA group were lower than those in the control group. In the comparison of the bone metabolism indexes, the contents of N-terminal propeptide of type I procollagen (P1NP) (SMD = 0.18, 95% CI = 0.03 to 0.32, P = 0.02), osteocalcin (SMD = 6.97, 95% CI = 3.46 to 10.48, P < 0. 0001), parathyroid hormone (PTH) (SMD = 0.38, 95% CI = 0.03 to 0.73, P = 0.03) and C-telopeptide of type 1 collagen (CTX) (SMD = 0.39, 95% CI = 0.03 to 0.75, P = 0.03) in serum from the DMA group were higher than those in serum from the control group. The serum content of 25-hydroxyvitamin D₃ (25(OH)D₃) (SMD = −0.63, 95% CI = −1.19 to −0.07, P = 0.03) in the DMA group was lower than that in the control group. There was no significant difference in serum alkaline phosphatase (ALP), calcium or phosphorus between the two groups (P > 0.05).

Conclusions

Type 2 diabetes microangiopathy can reduce the lumbar spine, femoral neck and Ward's triangle BMD and has a higher risk of osteoporosis or osteoporosis fractures. The levels of P1NP, PTH, CTX and OC in the serum of patients with type 2 diabetes microangiopathy are higher, and the lower 25(OH)D₃ content may be a mechanism by which DMA destroys bone metabolism balance.

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The effect of type 2 diabetes microangiopathy on bone mineral density and bone metabolism is still unclear.

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Type 2 diabetes microangiopathy can reduce the lumbar spine, femoral neck and Ward's triangle BMD.

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Type 2 diabetes microangiopathy has a higher risk of osteoporosis or osteoporosis fractures.

Imaging of Paget's Disease of Bone

Paget's disease is a metabolic bone disorder affecting the elderly and characterized by bone resorption followed by compensatory bone formation. Radiography is the imaging modality of choice for the diagnosis whereas bone scintigraphy helps stage the extent of the disease and assess response to treatment. MRI and CT are important imaging methods in the assessment of complications and surgical planning. Osteolytic lesions of Paget's first phase present with well-defined margins on radiographs, most commonly in the femur, pelvis, and skull. Cortical thickening, trabecular coarsening, bone marrow sclerosis, and deformities of long bones are present in the mixed- and late-sclerotic phases.

Prevalence of Low Serum Alkaline Phosphatase and Hypophosphatasia in Adult Patients with Atypical Femur Fractures

Hypophosphatasia (HPP) is a rare genetic disorder characterized by low serum alkaline phosphatase (ALP), its manifestations may include atypical femoral fractures (AFF). However, the prevalence of low serum ALP and HPP in patients with AFF remains unknown. We retrospectively analyzed ALP levels and clinical manifestations compatible with HPP in 72 adult patients with confirmed AFF by chart review. ALP values were compared with those of a control group of patients with prior proximal femoral fracture during antiresorptive treatment (n = 20). Among the AFF patients, 18 (25%) had at least one serum ALP value ≤ 40 IU/L, although in all but one case, at least one ALP value > 40 IU/L was also detected at another time point. Most low ALP values were associated with antiresorptive treatment (P = 0.049) and lowest levels of ALP did not differ between the AFF and the control groups (P = 0.129). However, low ALP values among AFF patients were associated with a higher rate of bilateral AFF (50% vs 22%, P = 0.025), metatarsal fracture (33% vs 7%, P = 0.006), and with trends for more frequent use of glucocorticoid (22% vs 8%, P = 0.089) and proton pump inhibitor (61% vs 44%, P = 0.220). In one AFF patient with low ALP and clinical suspicion of HPP, a rare pathogenic heterozygous variant of the ALPL gene was identified. In conclusion, low ALP values are common among subjects with AFF and mainly related to concomitant antiresorptive medication. Hence, low serum ALP has low specificity for HPP among AFF patients.

Sclerostin: From Molecule to Clinical Biomarker

Sclerostin, a glycoprotein encoded by the SOST gene, is mainly produced by mature osteocytes and is a critical regulator of bone formation through its inhibitory effect on Wnt signaling. Osteocytes are differentiated osteoblasts that form a vast and highly complex communication network and orchestrate osteogenesis in response to both mechanical and hormonal cues. The three most commonly described pathways of SOST gene regulation are mechanotransduction, Wnt/β-catenin, and steroid signaling. Downregulation of SOST and thereby upregulation of local Wnt signaling is required for the osteogenic response to mechanical loading. This review covers recent findings concerning the identification of SOST, in vitro regulation of SOST gene expression, structural and functional properties of sclerostin, pathophysiology, biological variability, and recent assay developments for measuring circulating sclerostin. The three-dimensional structure of human sclerostin was generated with the AlphaFold Protein Structure Database applying a novel deep learning algorithm based on the amino acid sequence. The functional properties of the 3-loop conformation within the tertiary structure of sclerostin and molecular interaction with low-density lipoprotein receptor-related protein 6 (LRP6) are also reviewed. Second-generation immunoassays for intact/biointact sclerostin have recently been developed, which might overcome some of the reported methodological obstacles. Sclerostin assay standardization would be a long-term objective to overcome some of the problems with assay discrepancies. Besides the use of age- and sex-specific reference intervals for sclerostin, it is also pivotal to use assay-specific reference intervals since available immunoassays vary widely in their methodological characteristics.

The Paget's disease of bone risk gene PML is a negative regulator of osteoclast differentiation and bone resorption

Paget's disease of bone (PDB) is characterized by focal increases in bone remodelling. Genome-wide association studies identified a susceptibility locus for PDB tagged by rs5742915, which is located within the PML gene. Here, we have assessed the candidacy of PML as the predisposing gene for PDB at this locus. We found that the PDB-risk allele of rs5742915 was associated with lower PML expression and that PML expression in blood cells from individuals with PDB was lower than in controls. The differentiation, survival and resorptive activity of osteoclasts prepared from Pml-/- mice was increased compared with wild type. Furthermore, the inhibitory effect of IFN-γ on osteoclast formation from Pml-/- was significantly blunted compared with wild type. Bone nodule formation was also increased in osteoblasts from Pml-/- mice when compared with wild type. Although microCT analysis of trabecular bone showed no differences between Pml-/- mice and wild type, bone histomorphometry showed that Pml-/- mice had high bone turnover with increased indices of bone resorption and increased mineral apposition rate. These data indicate that reduced expression of PML predisposes an individual to PDB and identify PML as a novel regulator of bone metabolism. This article has an associated First Person interview with the first author of the paper.

Is a Patient with Paget's Disease of Bone Suitable for Living Kidney Donation?-Decision-Making in Lack of Clinical Evidence

Living donor kidney transplantation is a widely performed medical procedure. Living kidney donation requires an in-depth health assessment of candidates. The potential living kidney donor must remain healthy after kidney removal. A consequence of donation can be a decrease in glomerular filtration rate (GFR), and donors can become at risk of developing chronic kidney disease (CKD). We present a rationale for potential living kidney donor withdrawal due to Paget's disease of bone (PDB) based on a literature review. The treatment for PDB includes the use of, for example, non-steroidal anti-inflammatory drugs (NSAIDs), which can lead to acute kidney injury (AKI) as well as CKD, or bisphosphonates, which are not recommended for patients with decreased GFR.

Paget's disease of bone and megaloblastic anemia in a 72‑year‑old patient: A case report and systematic literature review

Paget's disease of bone (PDB) is characterized by abnormal osteoclastic bone resorption with disorganized bone neo-formation, primarily affecting elderly (>55 years) patients. Although the majority of patients are asymptomatic, some patients may experience bone pain due to local periosteal involvement or osteoarthritic lesions in the spine; in addition, limb deformities may lead to secondary gait problems or degenerative joint changes. Anemia has an overall prevalence of 12-17% in elderly adults (>65 years old), with macrocytic anemia being the less common type. Megaloblastic anemia is a macrocytic anemia characterized by the presence of large, immature, nucleated cells (megaloblasts) in the blood, with the most common cause being a deficiency of folate and/or vitamin B12. We herein report the rare case of a 72-year-old male patient exhibiting both these conditions, with the aim of discussing the possible association between the two and, most importantly, the clinical management of the patient in a real-life setting over a period of 10 years. The patient was diagnosed based on clinical symptoms (bone pain), radiological imaging and specific laboratory tests, and received discontinuous courses of bisphosphonates and cyanocobalamin supplementation therapy, based mainly on aggravated symptomatology. A systematic literature review was also performed and revealed not only the scarcity of reports on similar cases, but also the mechanisms that may underlie the possible association of PDB with macrocytic anemia due to vitamin B12 deficiency in elderly patients.

Evaluating Patients for Secondary Causes of Osteoporosis

PURPOSE OF REVIEW

This review provides suggestions for the evaluation of patients with osteoporosis in order to assure that the diagnosis is correct, to identify potentially correctable conditions contributing to skeletal fragility and fracture risk, and to assist in individualizing management decisions.

RECENT FINDINGS

Some patients who appear to have osteoporosis have another skeletal disease, such as osteomalacia, that requires further evaluation and treatment that is different than for osteoporosis. Many patients with osteoporosis have contributing factors (e.g., vitamin D deficiency, high fall risk) that should be addressed before and after starting treatment to assure that treatment is effective and safe. Evaluation includes a focused medical history, skeletal-related physical examination, assessment of falls risk, appropriate laboratory tests, and rarely transiliac double-tetracycline labeled bone biopsy. Evaluation of patients with osteoporosis before starting treatment is essential for optimizing clinical outcomes.

Clinical Characteristics and Pathogenic Gene Identification in Chinese Patients With Paget's Disease of Bone

OBJECTIVE

To evaluate the clinical features of sporadic Paget's disease of bone (PDB) in China and further explore the underlying genetic abnormalities of the disease.

METHODS

Clinical characteristics, biochemical indices, bone turnover markers and radiographic examinations of the patients were collected. Genomic DNA was extracted from peripheral blood and whole-exome sequencing was carried out to identify the potential pathogenic genes. The pathogenicity of the variants was thereafter investigated by bioinformatics analysis.

RESULTS

A total of 50 patients (57.20 ± 15.52 years, male/female: 1.63: 1) with PDB were included and the mean onset age was 48.34 years (48.34 ± 17.24 years). 94.0% of the patients exhibited symptomatic patterns described as bone pain (86.0%), elevated skin temperature at the lesion site (26.0%), bone deformity (22.0%) and local swelling (18.0%). The most frequently involved lesion sites were pelvis (52.0%), femur (42.0%), tibia (28.0%), skull (28.0%) and spine (18.0%), respectively. Additionally, 40.0% of them accompanied with osteoarthritis, 14.0% with pathological fractures, and the misdiagnosis rate of PDB was as high as 36.0%. Serum level of alkaline phosphatase was significantly increased, with the mean value of 284.00 U/L (quartiles, 177.00-595.00 U/L). Two heterozygous missense mutations of SQSTM1 gene (c.1211T>C, M404T) and one novel heterozygous missense mutation in HNRNPA2B1 gene (c.989C>T, p. P330L) were identified in our study. Moreover, several potential disease-causing genes were detected and markedly enriched in the pathways of neurodegeneration (including WNT16, RYR3 and RYR1 genes) and amyotrophic lateral sclerosis (ALS, including NUP205, CAPN2, and NUP214 genes).

CONCLUSION

In contrast to Western patients, Chinese patients have an earlier onset age, more severe symptoms, and lower frequency of SQSTM1 gene mutation (4.0%). Moreover, a novel heterozygous missense mutation in HNRNPA2B1 gene was identified in one male patient with isolated bone phenotype. As for other genetic factors, it was indicated that WNT16, RYR3, RYR1, NUP205, CAPN2 and NUP214 genes may be potential pathogenic genes, pathways of neurodegeneration and ALS may play a vital role in the pathogenesis of PDB.

Total hip arthroplasty and Paget's disease: case report and literature review

Paget's disease (PDB) is a chronic osteopathy more common in male, Caucasic, European population, after the age of 50 years, that can lead to bone deformities. A challenging surgical solution for affected hip with severe hip osteoarthritis is total hip replacement (THA). We describe a case of THA in a 71-year-old patient with PDB and we present a literature review. In particular we find out that more studies comparing cementless THA with cemented one are necessary, in order to understand if one implant is better than the other.

A novel therapeutic strategy for skeletal disorders: Proof of concept of gene therapy for X-linked hypophosphatemia

Adeno-associated virus (AAV) vectors are a well-established gene transfer approach for rare genetic diseases. Nonetheless, some tissues, such as bone, remain refractory to AAV. X-linked hypophosphatemia (XLH) is a rare skeletal disorder associated with increased levels of fibroblast growth factor 23 (FGF23), resulting in skeletal deformities and short stature. The conventional treatment for XLH, lifelong phosphate and active vitamin D analogs supplementation, partially improves quality of life and is associated with severe long-term side effects. Recently, a monoclonal antibody against FGF23 has been approved for XLH but remains a high-cost lifelong therapy. We developed a liver-targeting AAV vector to inhibit FGF23 signaling. We showed that hepatic expression of the C-terminal tail of FGF23 corrected skeletal manifestations and osteomalacia in a XLH mouse model. Our data provide proof of concept for AAV gene transfer to treat XLH, a prototypical bone disease, further expanding the use of this modality to treat skeletal disorders.

Medication Management of Selected Pathological Jaw Lesions

Most jaw lesions are treated surgically. Areas of abnormal proliferation or destruction in bone are commonly treated by regional curettage, excision, or resection. However, surgery is invasive and leaves a defect where the lesion was removed. Surgical trauma to adjacent healthy tissue, including vital neurovascular bundles is often unavoidable, and can be especially traumatizing to the pediatric patient. Select jaw lesions with well-studied nonsurgical pharmaceutical treatments are presented here.

Long-Term Efficacy of Intensive Zoledronate Therapy and Predictors of Retreatment in Paget's Disease of Bone

Despite the current debate on the best therapeutic approach, i.e. symptomatic vs intensive strategy, one zoledronate (Zol) infusion is effective in most patients with Paget's disease of bone (PDB), whereas few need retreatment, whose predictors are not well established. We aimed to evaluate long-term efficacy of intensive Zol therapy and predictors of retreatment in PDB. Pagetic complications, clinical and biochemical response to Zol together with frequency of retreatment were retrospectively assessed in forty-seven PDB patients (age, mean ± SD: 72.5 ± 8.9 years, M/F: 24/23; symptomatic/asymptomatic: 16/31). Statistical analysis for retreatment prediction were based on Mann-Whitney U test, Pearson's Χ2 and ROC curve analysis. During seven-year follow-up, all patients achieved pain relief and only one underwent arthroplasty. Bone alkaline phosphatase (BAP) detected three non-responder (6%) and six relapsing (13%) patients needing retreatment. Retreated patients had less old age (66.1 ± 11.2 vs 74.0 ± 7.7 years), higher frequency of polyostotic disease (78% vs 40%) and higher baseline (96.5 ± 24.8 vs 44.9 ± 27.7 mcg/l) and post-Zol nadir BAP levels (24.7 ± 24.1 vs 8.1 ± 4.1 mcg/l) than patients treated once (p < 0.05 for all comparisons). In multivariate analysis both serum baseline and post-Zol nadir BAP significantly predicted retreatment (OR 1.09, 95%CI 1.01-1.17 and 1.29, 1.03-1.62, respectively), with ROC curve analysis showing the greatest accuracies for threshold values of 75.6 and 9.9 mcg/l (sensitivity 88 and 90%, specificity 94 and 86%, AUC 0.92 and 0.93, respectively). Our data in mostly asymptomatic, metabolically active PDB patients treated with intensive Zol therapy show a negligible incidence of pagetic complications and long-term optimal disease control, with BAP being the best predictor of retreatment.

Clinical and demographic aspects of Paget disease of bone: A multicentric study from Turkey

OBJECTIVE

Paget disease of bone (PDB) is a metabolic bone disease that has been rarely reported in the Eastern countries. This study aimed to evaluate the clinical and demographic characteristics of patients with PDB followed up at endocrinology clinics in Turkey.

METHODS

An invitation was sent to tertiary endocrinology clinics to complete a survey on the demographic, clinical, radiological, and laboratory parameters, as well as treatment modalities of patients with PDB. This study enrolled clinically and radiologically proven 185 patients with PDB from 18 endocrinology centers based in 10 cities of Turkey.

RESULTS

This cohort of PDB had female preponderance (women/men: 105/80) with a mean age, during diagnosis, of 57±10 years. Most of the patients (59.6%) were symptomatic at diagnosis. Bone pain and headache were the predominant clinical symptoms. Polyostotic disease was observed in 67.5% (n=125) of patients. Frequently affected bones were skull (41.6%), pelvis (53.5%), spine (41%), and femur (25.4%). Moreover, 17 patients with skull involvement had hearing loss. Mean serum alkaline phosphatase (ALP) level (552±652 IU/L; range: 280-5762 IU/L) was over the normal reference cutoff with normal serum calcium levels. Intravenous bisphosphonates (zoledronic acid, 5 mg; pamidronate, 60-90 mg) were the most used drugs (75%) for the treatment of PDB. Most of the patients (87.1%) treated with intravenous bisphosphonates responded well, with a decrease in serum ALP level (117±114 IU/L) in the 12th month of therapy. Furthermore, 16 patients relapsed after the second year of therapy; 3 patients did not respond to the initial intravenous bisphosphonate treatment.

CONCLUSION

The patients with PDB followed up by endocrinology clinics of Turkey exhibited polyostotic disease with classical clinical, radiological, and biochemical features and women's predominance with good response to intravenous bisphosphonate therapy.

Genetic Determinants of Paget's Disease of Bone

PURPOSE OF REVIEW

To provide an overview of the role of genes and loci that predispose to Paget's disease of bone and related disorders.

RECENT FINDINGS

Studies over the past ten years have seen major advances in knowledge on the role of genetic factors in Paget's disease of bone (PDB). Genome wide association studies have identified six loci that predispose to the disease whereas family based studies have identified a further eight genes that cause PDB. This brings the total number of genes and loci implicated in PDB to fourteen. Emerging evidence has shown that a number of these genes also predispose to multisystem proteinopathy syndromes where PDB is accompanied by neurodegeneration and myopathy due to the accumulation of abnormal protein aggregates, emphasising the importance of defects in autophagy in the pathogenesis of PDB. Genetic factors play a key role in the pathogenesis of PDB and the studies in this area have identified several genes previously not suspected to play a role in bone metabolism. Genetic testing coupled to targeted therapeutic intervention is being explored as a way of halting disease progression and improving outcome before irreversible skeletal damage has occurred.

Stress Fracture of the Femoral Shaft in Paget's Disease of Bone: A Case Report

Paget’s disease of bone (PDB) is a progressive bone disorder characterized by increased osteoclast-mediated bone resorption and abnormal bone formation. Incomplete atypical femoral fracture, appearing radiographically as a stress fracture at the lateral aspect of the femur, is an uncommon low-trauma fracture frequently seen in association with long-term bisphosphonate therapy. We describe the case of a 61-year-old female patient with PDB who developed a stress fracture at the lateral femoral cortex after 5 doses of intravenous bisphosphonate. The conservative treatment plan included discontinuation of bisphosphonate, a continuation of calcium and vitamin D supplementation, and limited weight-bearing for 3 months. The patient’s pain level gradually improved after switching to the new treatment plan. At the latest follow-up, approximately 5 years after the initiation of conservative treatment, the patient remained pain-free, and her PDB was well-controlled. However, the fracture line was still visible on the most recent radiograph. Although it remains unclear whether a stress fracture at the lateral femoral cortex occurred due to bisphosphonate therapy or PDB, this case highlights the importance of careful evaluation of any lesion that appears in PDB patients receiving bisphosphonate therapy.

Paget’s disease of bone: Report of 11 cases

BACKGROUND

Paget’s disease of bone (PDB) is a rare metabolic bone disease in China and is characterized by increased bone resorption and disorganized bone formation. The main clinical symptoms of PDB are focal or multiple bone pain and deformity with high disability. The disease has high missed diagnosis and misdiagnosis rates. This report summarizes the clinical manifestations, imaging and pathological features, and treatments of 11 patients with PDB at our hospital from 1993 to 2020 in order to improve the recognition and prognosis of PDB.

CASE SUMMARY

There were eight male and three female patients whose average age was 48.7 ± 11.0 years with a PDB course of 1-16 years. Nine patients had bone pain and bone deformities in different parts of the body, the majority of which involved the long bones. Laboratory examinations revealed elevated serum alkaline phosphatase (ALP) in all patients with an average of 618 ± 460 IU/L (normal range 0-130 IU/L), and serum calcium and phosphorus levels were in the normal range. Imageology showed that osteolysis was usually combined with osteosclerosis and/or bone deformities in single or multiple bones. ^99mTc-methylene diphosphonate bone scintigraphy revealed increased radionuclide uptake in the bone lesions. Six patients underwent bone tissue biopsy, and the typical pathological changes were a mosaic structure of the bone trabeculae with irregularly arranged cement lines and multinuclear osteoclasts. Ten of the 11 patients were effectively treated with bisphosphonates.

CONCLUSION

Early diagnosis of the rare disease PDB can be made through elevated ALP levels and typical presentations on bone X-ray and from bone tissue biopsy.

Epigenetic analysis of Paget's disease of bone identifies differentially methylated loci that predict disease status

Paget's disease of bone (PDB) is characterized by focal increases in disorganized bone remodeling. This study aims to characterize PDB-associated changes in DNA methylation profiles in patients' blood. Meta-analysis of data from the discovery and cross-validation set, each comprising 116 PDB cases and 130 controls, revealed significant differences in DNA methylation at 14 CpG sites, 4 CpG islands, and 6 gene-body regions. These loci, including two characterized as functional through expression quantitative trait-methylation analysis, were associated with functions related to osteoclast differentiation, mechanical loading, immune function, and viral infection. A multivariate classifier based on discovery samples was found to discriminate PDB cases and controls from the cross-validation with a sensitivity of 0.84, specificity of 0.81, and an area under curve of 92.8%. In conclusion, this study has shown for the first time that epigenetic factors contribute to the pathogenesis of PDB and may offer diagnostic markers for prediction of the disease.

Paget's Disease of Bone: Osteoimmunology and Osteoclast Pathology

PURPOSE OF REVIEW

The purpose of this review is to recognize clinical features of Paget's disease of bone and to describe how the osteoclast, a myeloid-derived cell responsible for bone resorption, contributes to the disease.

RECENT FINDINGS

Recent studies have identified several variants in SQSTM1, OPTN, and other genes that may predispose individuals to Paget's disease of bone; studies of these genes and their protein products have elucidated new roles for these proteins in bone physiology. Understanding the pathologic mechanisms in the Pagetic osteoclast may lead to the identification of future treatment targets for other inflammatory and autoimmune diseases characterized by abnormal bone erosion and/or osteoclast activation.

Fracture of tibial tuberosity in an adult with Paget's disease of the bone - An interesting case and review of literature

Introduction

Paget's disease of the bone is a non-malignant skeletal disorder characterized by focal abnormalities in bone remodelling at one or more skeletal sites. Pathological fractures occurring from trivial injuries are a well-known clinical presentation in patients with Paget's disease. An avulsion fracture of the tibial tuberosity is an infrequent injury and has an extremely low occurrence in adults, with only a few cases reported in literature. We describe a case of a patient with undiagnosed Paget's Disease of the bone, sustaining a pathological avulsion fracture of the tibial tuberosity.

Case report

A 54-year-old male presented with right knee pain after his knee gave way whilst standing in the goal area during a game of football, twisting his right ankle and falling. Plain radiographs of the knee revealed an avulsion fracture of the tibial tuberosity with abnormal modelling of the proximal half of the tibia. An MRI confirmed a diagnosis of Paget's disease of the bone. The patient underwent open reduction internal fixation. At 3 months follow up, the patient had good knee range of motion from 0 to 100 degrees and by 6 months he had returned to his usual activities.

Conclusion

We describe a unique case of tibial tuberosity avulsion fracture in an adult with PDB. Treatment was successful with cannulated screws and tension band wiring. Patients with PDB who fracture present with diagnostic and operative challenges, it is vital to progress with caution in the postoperative rehabilitation phase.